The invention relates to a seat frame of a vehicle seat.
Such seat frame of a vehicle seat comprises a first frame part, a second frame part and a fitting which pivotally connects the first frame part with the second frame part about a swivel axis. With the first frame part a first fitting part of the fitting and with the second frame part a second fitting part of the fitting is connected, which are adjustable relative to each other for pivoting the frame parts. At least one of the first fitting part and the second fitting part has an annular collar surface extending around the swivel axis and pointing radially to the outside, via which the associated fitting part is connected with an annular bearing portion of the associated frame part, which delimits an opening.
Such fitting can be formed as rotary fitting or as detent fitting. When the fitting is formed as rotary fitting, the two fitting parts for example realize a wobble transmission in which, driven by an eccentric mounted on the first fitting part and rotatable relative to the first fitting part, the second fitting part can be put into a wobbling rotary movement relative to the first fitting part, so as to pivot the second frame part connected with the second fitting part relative to the first frame part connected with the first fitting part.
A rotary fitting of this kind is known for example from DE 10 2008 028 105 A1, in which the first fitting part is formed as a hollow gear carrying an internal toothing and the second fitting part is formed as an internal gear carrying an external toothing, and via an eccentric the internal gear can be rotated relative to the hollow gear in a wobbling manner.
The invention however also relates to a seat frame with a fitting formed as detent fitting, as it is known for example from DE 20 2008 003 706 U1. In the detent fitting known from DE 20 2008 003 706 U1, locking bolts are radially shiftably arranged on a first fitting part, which can be brought in engagement with a toothing of a second fitting part pivotally mounted relative to the first fitting part, so that in a locked condition the fitting parts cannot be pivoted relative to each other, whereas in an unlocked condition an adjustment of the fitting parts relative to each other is possible.
The fitting serves for pivotally connecting the two frame parts of the seat frame with each other. For example, when a backrest and a seat part of a vehicle seat are coupled with each other via the fitting, large forces—as a result of the load exerted on the backrest by a vehicle occupant due to weight forces acting in normal operation or load forces acting in the case of a crash—must be dissipated via the fitting and be passed from the backrest via the fitting into the seat part and thereby into the vehicle body. These load forces chiefly act as torques about the swivel axis of the fitting—with the backrest acting as lever—, so that the attachment of the fitting to the frame parts of the seat frame must be formed so stable that the forces and moments acting between fitting and frame parts can be dissipated in a reliable way, without the fitting parts being detached from the associated frame parts.
In today's seat frames a fitting part frequently is welded to the associated frame part for example by means of laser welding, in order to create a firm connection. However, it should be taken into account that when fitting the fitting part into the associated frame part by inserting the collar surface into the associated opening of the frame part, tolerances can occur, which can lead to a considerable joining gap between the collar surface of the fitting part and the bearing portion of the frame part. When the fitting part is not centrically fitted into the associated frame part, this joining gap is non-uniform as a result of a varying distance between the collar surface and the bearing portion, which is disadvantageous in particular when the width of the joining gap exceeds the bridging of a gap achievable with a used welding method.
As a result, welding spatters can occur to an increased extent, which are deposited on the seat frame or also on the manufacturing facility. In addition, seam collapses or seam reinforcements can occur as a result of deposited welding spatters, holes can occur in the welding seam, and the welding seam at least partly can have a reduced strength. All this can contribute to an increased scrap rate during manufacture, also can lead to a slower welding and thus process speed, and possibly can be monitored only with difficulty.
In a seat frame known from DE 10 2010 043 625 A1, a reinforcement part is provided for connecting a fitting part with a frame part, which produces the connection of the fitting part formed as hollow gear to the frame part and at the same time reinforces the point of attachment of the fitting part to the frame part for an improved load dissipation.
In a fitting known from WO 2010/020340 A2 bearing points are provided between an external element and an internal element, which should serve to adjust a gap between the external element and the internal element with a defined minimum width. The width should not fall below this minimum width. For connecting the external element and the internal element, the gap is filled by welding by using a filler material.